abis_rsl: Add support for extended CBCH to rsl_sms_cb_command()

Now that OsmoBTS understands about extended CBCH, let's at least
update the BSC side function to allow for other code to generate
such messages.

Change-Id: I77a16b75ce311d63fb022475c8ff25fbbcee7f55
diff --git a/include/osmocom/bsc/abis_rsl.h b/include/osmocom/bsc/abis_rsl.h
index 098d2e6..ec63090 100644
--- a/include/osmocom/bsc/abis_rsl.h
+++ b/include/osmocom/bsc/abis_rsl.h
@@ -90,7 +90,7 @@
 /* SMSCB functionality */
 int rsl_sms_cb_command(struct gsm_bts *bts, uint8_t chan_number,
 		       struct rsl_ie_cb_cmd_type cb_command,
-		       const uint8_t *data, int len);
+		       bool use_extended_cbch, const uint8_t *data, int len);
 
 /* some Nokia specific stuff */
 int rsl_nokia_si_begin(struct gsm_bts_trx *trx);